258 
PALAEONTOLOGY OF NEW YORK. 
smaller extremity is eight mm., and the chamber of habitation has a diameter 
of twenty-three mm. 
This species, of which only one specimen has been observed, is distinguished 
from 0. procerus by its large apical angle, the concavity of the septa, and the 
greater excentricity of the siphuncle. 
Formation and locality. The Schoharie grit at Schoharie, N. Y. 
Orthoceras carnosum, n. sp. 
PLATE XXXV, FIG. 11. 
Shell small, straight, regularly enlarging to a point near the middle of the 
chamber of habitation. Transverse section broadly elliptical. Apical angle 
about 9°. Apex unknown. 
Chamber of habitation short, somewhat gibbous; point of greatest trans-: 
verse section near the middle, whence the shell contracts slightly, and 
again expands before reaching the aperture, forming a shallow constric¬ 
tion. Air-chambers regular, having a depth of from two to three mm., and 
less near the base of the chamber of habitation. 
Septa smooth, having a concavity equal to an arc of 109°. Sutures straight 
and horizontal. 
Siphuncle subcentral, large, having a diameter of two mm. where the 
diameter of the tube measures ten mm. The elements have not been 
observed in its passage through the chambers. 
Test thin, rarely preserved. Surface marked by fine, regular, lamellose, 
transverse, arching striae, six in the space of two mm., crossed by finer, 
longitudinal, cancellating striae. The striae are curved, forming a broad, 
distinct sinus over the ventral side. 
The internal mould is essentially smooth, with the chamber walls flat, and 
the sutures but little impressed. 
The only individual yet observed, which is referred to this species, has a 
length of fifty-eight mm., including the outer chamber, with ten of the 
attached air-chambers. 
